Steam-turbine.



0. LASCHE.

STEAM TURBINE.

APPLICATION FILED DEC. 12, 19M. 1,171,216. Patented Feb.8,1916.

Witnesses: Inventor:

Osfiar- Lasclye,

Hiso ttor'neg.

TM cum m vuuouaAm-l 00.. WASHINGTON, D. c.

ject the steam to UNITED STATES PATENT OFFICE.

OSKAR LASCHE, 0F CHARLOTTENBURG, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

STEAM-TURBINE.

To all whom it may concern:

Be it known. that I, OSKAR LASCHE, a subject of the King of Saxony, residing at harlottenburg, Germany. have invented certain new and useful Improvements in Steam-Turbines, of which the following is a specification.

This invention relates to elastic fluid turbines, and its object is to remove the water from steam in the low pressure stages of a steam driven turbine.

In the passage of the motive fluid through a multi-stage turbine, the gradual extraction of energy in the form of heat reduces the steam to a. state of saturation in the lower pressure stages, so that when it en ters the last one or two bucket wheels its moisture content is frequently as high as ten per cent. The particles of water entrained by the steam due chiefly to their relatively high velocity have a destructive action on the buckets in said stages.

It is found that the buckets of the low pressure wheels are worn principally at the outer ends. This fact may be explained from the circumstance that the drops of water which form i the low pressure part of the turbine during the expansion of the steam are, by reason of their greater specific gravity, thrown outward by centrifual force, so that the steam which leaves the outer ends of the wheel buckets contains a greater amount of moisture than the steam leaving the inner ends of the buckets. The steam flows through the nozzles in this same stratified condition, the wetter steam striking the outer ends of the buckets on the succeeding wheel, and thus causing greater wear at these points. The nozzles at the lower side of the casing will be worn more than those at the top, because the wet heavier steam naturally gravitates to the bottom of the casing. An obvious way to overcome this ditliculty would be to superheat the steam at the outset to a degree which would cause it to flow through the entire machine in a dry condition. This, however, would require the initial superheat to be so great as to be impracticable. Another mode 0 reaching the same result would be to suban intermediate superheating operation. But in either case, the cost of the additional plant would, in a large majority of cases, be prohibitive.

By the present invention, the water 0 Specification of Letters Patent.

Application filed December 12, 1914..

Patented Feb. 8, 1916.

Serial No. 876,801.

condensation is taken out of the steam in the low pressure portion of the turbine by a simple mechanical device, comprising a cutting away of the outer sides of the nozzles to a point beyond the periphery of the buckets to which said nozzles deliver steam, and also the provision of drain passages in the lower side of the wheel chambers in a horizontal turbine, through which the water can escape to the condenser or to any other suitable receptacle.

The accompanying drawing is a longitudinal vertical section of the low pressure end of a horizontal turbine embodying my invention.

The casing 1. is divided by l'liaphragms 2 into wheel chambers or stages in which the bucket wheels 3 revolve. Nozzles l are provided in the diaphragms. and those which deliver steam to the last two or three of the low pressure wheels are so constructed that at their mouth they project slightly beyond the periphery of the wheel buckets. The nozzles may be cut away at their outer sides to eiiect this result as indicated at 5; either entirely, or at intervals forming a plurality of grooves running lengthwise of the machine. ()ther equivalent means for etl'ccting a separation of the water from the steam will readily suggest themselves to the skilled engineer. In. this way, the small outer and wetter stratum of the total jet of steam does not come in contact with the wheel buckets, but passes outside the periphery of the wheel, and collects in the spaces or pockets 6 between the diaphragms', from which it may be drained off through passages 7, either to the exhaust conduit 8 leading to the condenser, or to any other suitable receptacle.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

hat I claim as new and desire to secure by Letters Patent of the United States, is

1. The combination with an elastic fluid turbine provided with bucket wheels and nozzles for directing the elastic fluid against them, of means fol-mi, 1g a passage in the nozzles whieh beyond the periphery of the next succeeding bucket wheel so that fluid of condensation uuiy escape past the periphery of sueh buckets.

L. Au elustir' tiuid turbine having stage nozzles provided with means for directing Water of condensation past the periphery of the succeeding bucket wheel.

3. An elastic fluid turbine having its low pressure stage nozzles cut away at their outer sides to permit water of condensation to escape past the periphery of the succeeding bucket wheel.

4. An elastic fluid turbine having its low pressure stage nozzles cut away at their outer sides to permit Water of condensation to escape past the periphery of the succeeding hueket Wheel, and drain passages opening from the spaces between the diaphragms.

5. An elastic fluid turbine divided into ste 'es, each stage having a fluid dischargingg device and :1 rotor nieuns acted upon by the fluid from said device, the outer surface of the said device being at a greater distance from the rotor axis than the ends of the rotor buckets cooperating therewith to permit condensation to be discharged be yond the path of said bucket In witness whereof, I have my hand this 5th day of November 1914.

()SKAR LA SCHE,

\Vitnesses:

ERICK EBERLEE, GUs'rAv Ht'iLBRocK.

maples of this patent may be obtained for five cents each, by addressing the Commissioner of Patenta. Washington, D. C.

hereunto set 30 

